Stencil sheet



Patented June 19, 1928.

UNITED STATES PATENT OFFICE.

HERBERT L. SHALLCROSS, OF COLLINGDALE, PENNSYLVANIA, ASSIGNOR TO THE SHALLCROSS COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF DELAWARE.

STENCIL SHEET.

Ho Drawing.

This invention, generally stated, relates to stencil sheets and has more especial relation to a stencil sheet in whic-h'in contradistinction to a porous base of soft wax, there is applied thereto or impregnatedthereupon-a coating material or base having a type impressible coating composed of seed lac or other lac as a base, combined ...With nitrated cotton and camphor gum, as a hardener and binder commingled with ,castor oil as a tempering agent and "sperm oil or the like to keep the stencil in usable condition;

The object of my novel present-invention is in the provision of a novel'stenci'l sheet of the character above indicated in which a novel coating or impregnating material characteristically different from anything which has been heretofore developed, which when applied to the foundation sheet results in a much stronger stencil sheet, thereby overcoming the weakness in present day stencils, which is at all times ready for use by inserting the same in a writing machine and typing thereon. v

A further object of the present invention is to provide a novel stencil sheet of the character stated and above indicated in whichthere is used as a base for the stencil sheet seed lac or other suitable lacin combination with a solution of nitrated cotton as a hardener and binder cornmingled with certain oils for the attainment of a much more efiicient and stronger stencil sheet thereby overcoming the weakness of present day stencils, as is well known now to the trade and upon the market.

To the above ends my presentinvention resides in the coating or impregnating of a stencil sheet of the character stated with a preparation composed of a base of suitable lac, camphor gum and nitrated cotton, as a hardener or binder.

A further object of the present-invention is to provide a stencil sheet of the character. stated coated or impregnated with a material composed of a suitable lac, nitrated cotton, camphor gum and a tempering agent, as castor oil.

' A further object of the present invention is to provide a stencil sheet of the charact-er above stated, coated or impregnated with the materials above itemized in connection 'Wlth sperm or other suitable oil to parts of alcohol.

Application filed October 17, 1927. Serial No. 226,817.

maintain the stencil sheet in pliable and usable condition.

The invention consists of the novel stencil described and finally prised of a base of seed lac or other suitable lac dissolved in alcohol; a solution of nitrated cotton treated with a suitable sol- .vcnt including camphor gum, and castor and sperm or other suitable oils.

The proportions of ingredients I prefer to employ in the novel coating or impregnation of a-stencil sheet may be set forth, as follows, to wit:

As a base I prefer to employ substantially six ounces of seed lac or other suitable lac dissolved in about approximately 1 to 10 To'this solution I add substantially three ounces of nitrated cotton dissolved in about 100.parts of a suitable solvent, to which latter has been added substantially 1 ounce of camphor gum. To the solution thus prepared I add as a tempering agent substantially three ounces of castor oil.

In order to provide pliability to the stencilsheet, I add to the ingredients aboie enumerated, approximately fifty ounces .of sperm or other suitable oil. In this corinection it may be noted that the said lac or other lac is used as a base, and that the solution of nitrated cotton is used as .ahardener or binder, so that a much stronger stencil sheet is provided than heretofore, thus overcoming the weakness of present day stencil sheets.

Suitable coloring matter maybe added at any desired stage of the commingling of the above ingredients, such as a dye or carbon able manner as by drawing one surface of said paper into contact with or floating it upon the surfaceot said composition, and then if necessary, removing or draining off any excess of the composition or material by drawing the coated sheet over a taut wire or straight edge or the like, and the coated sheet then hung up to dry. 1

There is in practice suflicient evaporation of the alcohol. in about a half-hours time to permit handling of the sheet, which when dry is ready for use. storage and handling, sheets of o 1l paper may be packed between the stencil sheets whose tackiness if presentis hardly appreciable, the oil sheets being preferably removed before putting the stencil sheets to use.

My novel stencil sheet is highly economical of .ink during the operation of producing stencil copies therefrom, and there is no necessity for blotting the stencil copies or to interleave sheets therewith,as sometimes now has to be done. The stencil copies can be handled at once without danger of smearing the ink thereon, and the stencil sheet preserves its original form, notwithstanding wrinkling, crumplin and rough handling, and it will be found 0 be elastic, and does not permanently stretch, nor do the fibres of the tissue base loosen or ull apart.

My invention is not limited to the exact proportions given, and within the scope of the appended claims,various substitutes or equivalents may be used for the base hardener and binder, as will be understood by those skilled in chemistry.

I have found in practice that by my novel stencil sheet made as above described, the coating remains throughout an extended period of time practically unchanged, and without preliminary moistening is capable of being removed or displaced, as by the blow of the type of a, writing machine, or by the pressure of ahand stylus, from or on the -underlying foundation sheets, leaving the open texture fibres of the latter practically intact for the support of the centers of loop letters. It will further be found that the spaces corresponding with the lines of the For transportation,

characters will be substantially clear of the coating material, so as to permit the passage of ink therethrough when the sheet is used in the ordinary manner, as in a stencil dupli-- eating machine.

Having-thus described my invention, what I claim as new and useful and desire to secure by Letters Patent, is:-

1. A stencil sheet adapted for conversion into a stencil by impact of type thereon, comprising a paper sheet of open texture, porous material, avmg a type nnpressible coating thereon, consisting of a base of lac dissolved in alcohol, and having added thereto dissolved nitrated cotton, camphor gum, and oils.

2. A stencil sheet adapted for conversion into a stencil by impact of type thereon, comprising a paper sheet of open texture, porous material, having a type impressible coating thereon, consisting of a base of lac dissolved in alcohol, and having added thereto dissolved nitrated cotton, camphor gum, castor oil and sperm'oil.

3. A'stencilsheet adapted for conversion into a stencil by impact of type thereon, comprising a paper sheet of open texture, porous material, iaving a type impressible coating thereon, consisting of a base of six ounces of lac dissolved in alcohol, and having added thereto about three ounces of dissolved nitrated cotton and about one ounce of camphor gum, and fifty-three ounces of oils.

4. A composition for coating or impreg natin a stencil sheet, which consists of a base having a type impressible coating including seed lac dissolved in alcohol,'dissolved nitrated cotton and cam hor gum, a tempering agent of castor Oll, equal in weight to said nitrated cotton, and a greater quantity of sperm oil.

5. A composition for coating or impregnating a stencil sheet which consists of about six ounces of seed lac dissolved in about one to ten parts of alcohol, about three ounces of dissolved nitrated cotton dissolved in one hundred parts of a solvent, one ounce of camphor gum, a tempering agent of about three ounces of castor oil, and about fifty ounces .of sperm oil.

HERBERT L. SHALLCROSS. 

